Mid-Year Review

Chemistry, Earth History, Infectious Disease, Lithosphere

Mid-Year Review

Chemistry, Earth History, Infectious Disease, Lithosphere

Chemistry- 8.P.1- Understand the properties of matter and changes that occur when matter interacts in an open and closed container.

Physical Properties- A characteristic that you can observe without changing the composition of the substance. Ex; Looks, smells, feels, sounds or tastes.

Chemical Properties- A characteristic that you can only observe by changing the identity of the substance. Ex; Flammability, reactivity, oxidation, and toxicity.

Physical Change- Any change that does not involve a change in the substance's chemical change. Ex; Wood chipper, liquid to gas, Ice to water. (Physical changes can be undone.

Chemical Change- Any change in matter that results in the formation of a new chemical substance. Ex; Eggs, Cake, tree burning. (Can't be reversed)

Elements- Simplest form of matter. Composed of a single kind of atom.

Compound- Made up of 2 or more atoms that are chemically combined.Mixtures- A combination of 2 or more substances that are not chemically combined.

Homogeneous- You can't see the individual parts of the mixtures.

Heterogeneous- You CAN see the individual parts of the mixtures.

The Periodic Table- A table of the chemical elements arranged in order of atomic number. Ex; Boron, Silicon, Copper.

Groups- Columns up and down of elements on the Periodic Table that share common properties.

Periods- The horizontal rows of the periodic table.

Metals- They are solid. They are shiny, good conductors of electricity and heat. They can be made into thin wires.

Non-metals- Brittle, not good conductors of both heat and electricity, and can gain electrons in chemical reactions. Some nonmetals are liquid.

Metalloids- have properties that are somewhat of a cross between metals and nonmetals, because of their unique conductivity properties (they only partially conduct electricity) they can be used as a semiconductor or in computer chip.

Atomic Number- The number of protons in the atom's nucleus.

Atomic Mass- The mass of the atom.

Protons- a particle of a positive electric charge in an atom.

Electrons- a particle of a negative electric charge in an atom.

Neutron- Same mass as a proton but without the electric charge.

Law of Conservation of Mass- States that matter cannot be created or destroyed; it can only be transferred from state to state.

Vocab- Compound, Matter, Solution, Atom, Mixture, Element

Earth History

Law of Superposition- The youngest rock is at the top and the oldest is at the bottom.

Index Fossils- Found in rock layers, rock layers of only 1 geological age.

Ice Cores- A cylinder of ice that tells us about Earths history. Contains carbon dioxide.

Geologic Time Scale- describe the timing and relationships between events that have occurred throughout Earth's history.

Relative Dating- Used to determine the age of a fossil by looking at its positions in the layers of sedimentary rocks.

Absolute Dating- Used to determine the exact age of a fossil.

Half-Life/Radioactive Decay-a nucleus of an unstable atom loses energy as it gets older.